Plastic caps or closures for fluid and viscous material dispensers are not new, and the plastic molding industry has provided a wide assortment of closures for spray-type containers, liquid dispensing containers and paste-type dispensers. Such closures are generally threaded or press-fitted to the top of a bottle tube or can, and are arranged to be opened easily so that the contents of the container may be dispensed through the closure.
However, in the past, most of these closures have been either tow-part devices with a body portion fitted to the container and a separate cap which is snapped or screwed to the body, or, in some instances, have comprised a body and a cap portion which are molded with a self-hinge, but wherein the cap is held against the body because the diameter of the opening of the body and the diameter of the cap have been selected so that the differential diameters of the two portions provide the retaining forces necessary to keep the cap in place on the body. Such closures are indicated by U.S. Pat. No. 3,300,104 (1967), RE 25703 (1964) and the like. Note also U.S. Pat. No. 2,778,533 (1957) which illustrates the method of molding a body and cap member with a strap-type hinge for providing an integral cap and body closure wherein the differential diameters hold the cap in place on the body.
However, utilitarian such prior art devices may be, I have found it desirable to provide a one-piece closure having a cap and body with a self-hinge about which the cap pivots to snapfit on to the body. I employ the tensioning force between the integral hinge and the orifice in the body, and the integral hinge and the button on the cap, to provide the necessary fluid-tight seal.